Sampling and Scrambling on a Chain of Superconducting Qubits

Michael R. Geller

doi:10.1103/PhysRevApplied.10.024052

← Back to search

Sampling and Scrambling on a Chain of Superconducting Qubits

Michael R. Geller

DOI 10.1103/PhysRevApplied.10.024052 · Physical Review Applied

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We study a circuit, the Josephson sampler, that embeds a real vector into an entangled state of n qubits, and optionally samples from it. We estimate two fidelity measures and a variety of entropies and entanglement measures for this circuit, versus depth, on the 16-qubit ibmqx5 chip. This provides a quantitative assessment of the actual performance of the circuit on a first-generation quantum computer. To assess its expressiveness, we also measure its ability to generate quantum chaos as measured by out-of-time-order correlators (OTOCs). We conjecture that OTOCs can be used to validate a source of pseudorandom unitaries with only a single instance, which has application beyond the Josephson sampler. The circuit requires nearest-neighbor controlled-Z gates on a chain and is especially well suited for first-generation superconducting architectures.